Airport traffic is increasingly dense both in the air and on the ground. Collisions between aircraft and various obstacles on the ground are more and more frequent, especially when an aircraft is returning to a parking position from a runway of an airport. For example, with a wide-body aircraft it is difficult for the pilot of the aircraft to see the wings and jet engines. The wings and jet engines are therefore particularly exposed to impacts with various objects such as:                other aircraft        airport infrastructure; and        airport support vehicles.        
This type of incident, in addition to the cost of repairing the aircraft, requires ground maintenance be carried out on the aircraft. This ground maintenance of the aircraft is financially detrimental to the company owning the aircraft.
To mitigate these collisional problems, airports are equipped with various means allowing centralized management of ground traffic. These means are especially airport surveillance radar, radio means, GPSs and transponders. However, the density of traffic in airports is such that these means are not enough to ensure the final guidance of aircraft to their parking position. In addition, these means are often ineffective when it is foggy for example and generally when meteorological conditions are bad or it is night. Human intervention is thus necessary in order to prevent any risk of the aircraft colliding with objects present on the ground in a taxiing zone.
Another way of avoiding collisions between an aircraft and objects present on the ground is to equip the aircraft with autonomous anticollision devices that complement existing means present in the airport. These anticollision devices especially make it possible to ensure the aircraft is protected over a very short distance with respect to stationary objects or objects possessing a low velocity of movement.
Among these means, devices including video cameras are especially used. Video cameras are however ineffective when meteorological conditions are poor. In addition, video-camera-based devices do not provide the pilot with precise information either on the distance between the aircraft and a potential obstacle, or on the relative velocity of the aircraft with respect to the obstacle.
To treat a wide angular field with a sufficient depth of field in a very short time, the video cameras may be equipped with zooms or rapid electronic focusing devices. The video cameras thus equipped are complex to implement and do not have the reliability required for an anticollision device.
Other devices based on the LIDAR (acronym for Light Detection And Ranging) may be used. Anticollision devices using LIDAR however have the same drawbacks as devices using video cameras.
Acoustic sensors may also be implemented in anticollision devices. Acoustic sensors are however very sensitive to interference and to perturbation of the propagation of the acoustic waves. All this makes the use of acoustic sensors difficult in an airport environment. The range of acoustic sensors is also too low, of about a few meters, to be suitable for an anticollision device.
Other anticollision devices use radar technologies such as ultra wideband radars. These devices run the risk of jamming other pieces of equipment such as the on-board navigation equipment of aircraft. Ultra wideband radars are therefore subject, when their use is permitted, to very restrictive regulations especially limiting the power of the emitted wave. The limitation of the emission power of these radars considerably decreases their field of use and especially their range. In addition, these radars do not possess, taken individually, an angular discrimination capacity. They therefore do not allow obstacles to be located with sufficient precision. Such radars possess attractive angular discrimination capacities only when they are grouped together into large arrays, thereby making implementation on-board an aircraft impossible.
Patent application FR 07 01927, having publication number 2 913 775, describes an effective solution for processing collision risk, in which a system of automotive radar sensors operating in the millimeters band is used.
This solution, although effective, may be subject, on account of the number of sensors implemented and their installation position, to both integration and cost constraints that make it difficult to implement on certain carriers.